返回键异常

Question

    在模拟器上按返回键，可以成功返回上一个Activity,而在真机上运行同一个程序，当从Activity A进入到Activity B，再进入到Activity C中，当从Activity C按两次返回键回到Activity A时，它会自动跳回到Activity C一次。
    这是为什么呢？怎么解决呢？

Answer 1

我不理解你所描述的： 当从Activity C按两次返回键回到Activity A时，它会自动跳回到Activity C一次。 是什么意思
点两次是双击，还是缓慢的两次？ 是doubleOnSnap的实现么？ 是Activity C → B→ C→ A  还是CBAC还是CAC 

Answer 2

就是点一次返回键，从Activity C返回到Activity B,再点一次返回键，从Activity B返回到Activity A，然后它自动跳回了 Activity C，然后再点返回键，就从Activity C 直接跳回到Activity A。

Answer 3

是不是在ActivityC中做了什么特殊处理了，影响了Activity 栈

Answer 4

public class ClassSheet2 extends Activity {
    /** Called when the activity is first created. */
 private TabHost tabHost;
 private String week="1";
 private ListView listView;  
 HashMap<String, String> map;    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.csheet);
        tabHost = (TabHost) this.findViewById(android.R.id.tabhost);
          tabHost.setup();
          tabHost.addTab(tabHost.newTabSpec("tab_1")
                         .setContent(R.id.tab1)
                          .setIndicator("一",getResources().getDrawable(R.drawable.tab_sel)));
          tabHost.addTab(tabHost.newTabSpec("tab_2")
                           .setContent(R.id.tab2).setIndicator("二",getResources().getDrawable(R.drawable.tab_sel)));
          tabHost.addTab(tabHost.newTabSpec("tab_3")
                         .setContent(R.id.tab3).setIndicator("三",getResources().getDrawable(R.drawable.tab_sel)));
          tabHost.addTab(tabHost.newTabSpec("tab_4")
                  .setContent(R.id.tab4).setIndicator("四",getResources().getDrawable(R.drawable.tab_sel)));
          tabHost.addTab(tabHost.newTabSpec("tab_5")
                  .setContent(R.id.tab5).setIndicator("五",getResources().getDrawable(R.drawable.tab_sel)));
          tabHost.addTab(tabHost.newTabSpec("tab_6")
                  .setContent(R.id.tab6).setIndicator("六",getResources().getDrawable(R.drawable.tab_sel)));
          tabHost.addTab(tabHost.newTabSpec("tab_7")
                  .setContent(R.id.tab7).setIndicator("日",getResources().getDrawable(R.drawable.tab_sel)));        
          final TabWidget tw = tabHost.getTabWidget();
          for (int i = 0; i < tw.getChildCount(); i++) {
                 TextView textView = (TextView) tabHost.getTabWidget().getChildAt(i).findViewById(android.R.id.title);
                textView.setTextColor(ClassSheet2.this.getResources().getColor(android.R.color.white));
                tw.getChildAt(i).getLayoutParams().height = 50;
                tw.getChildAt(i).getLayoutParams().width = 45;
                }          
          tabHost.setCurrentTab(0);
          new WSAsyncTask().execute();
          tabHost.setOnTabChangedListener(new OnTabChangeListener() {
@Override
public void onTabChanged(String tabId) {
// TODO Auto-generated method stub
System.out.println(tabId);
if(tabId=="tab_1"){
week="1";
}else if(tabId=="tab_2"){
week="2";
}else if(tabId=="tab_3"){
week="3";
}else if(tabId=="tab_4"){
week="4";
}else if(tabId=="tab_5"){
week="5";
}else if(tabId=="tab_6"){
week="6";
}else if(tabId=="tab_7"){
week="7";
}
new WSAsyncTask().execute();
}

});
          
         
   }
      
    class WSAsyncTask extends AsyncTask<Object, Object, Object>   
    { 
      ArrayList<HashMap<String, String>> list = new ArrayList<HashMap<String,String>>();
      String result = "";   
      @Override  
      protected Object doInBackground(Object... params)   
      {       
       try  
       {
             String serviceUrl = "http://"+FzxyLogin.ip+"/GuestWebService.asmx?WSDL";   
             String methodName = "SearchClassSyllabus";   
             SoapObject request = new SoapObject("http://tempuri.org/",methodName);   
             request.addProperty("termId", getIntent().getStringExtra("termId"));  
             request.addProperty("className", getIntent().getStringExtra("className")); 
             request.addProperty("week", week);   
             SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);   
             envelope.bodyOut = request;
             envelope.dotNet=true;
             (new MarshalBase64()).register(envelope);
             HttpTransportSE ht = new HttpTransportSE(serviceUrl); 
             ht.debug=true;
              ht.call("http://tempuri.org/"+methodName, envelope);   
             if (envelope.getResponse() != null)   
              {   
                 SoapObject soapObject = (SoapObject) envelope.getResponse();
               System.out.println(soapObject.getProperty(1));
                 int count=soapObject.getPropertyCount();
                 System.out.println(count);
                 result+=soapObject.toString();
                  for(int i=0;i<count;i++){
                   String str=soapObject.getProperty(i).toString();
                   String[] sss=str.split("=|;");
                       map = new HashMap<String, String>();
                      sss[1]=sss[1]+"-"+(Integer.parseInt(sss[1])+1);
                      map.put("Jieci", sss[1]);
                      map.put("CourseName", sss[3]);
                      map.put("Teacher", sss[5]);
                      map.put("ClassRoom", sss[7]);
                      map.put("Weekday", sss[9]);
                      list.add(map);
                      result+=(map.get("Jieci")+map.get("CourseName")+map.get("ClassRoom")
                       +map.get("Teacher")+map.get("Weekday")+map.get("Xingqi")+"\n");
                      System.out.println(result);
                   }
                  
                  
                  if(week=="1"){
                    listView=(ListView) findViewById(R.id.listView1);
listView.post(new Runnable() {
@Override
public void run() {
SimpleAdapter simpleAdapter = new SimpleAdapter(ClassSheet2.this, list,
R.layout.csoutput,new String[] { "Jieci", "CourseName","ClassRoom",
"Teacher", "Weekday" }, new int[] { R.id.Jieci,R.id.CourseName, 
R.id.ClassRoom,R.id.Teacher, R.id.Weekday});
listView.setAdapter(simpleAdapter);
}
});
                  }
                  
                  if(week=="2"){
                      listView=(ListView) findViewById(R.id.listView2);
   listView.post(new Runnable() {
   @Override
   public void run() {
   SimpleAdapter simpleAdapter = new SimpleAdapter(ClassSheet2.this, list,
   R.layout.csoutput,new String[] { "Jieci", "CourseName","ClassRoom",
   "Teacher", "Weekday","Xingqi" }, new int[] { R.id.Jieci,R.id.CourseName, 
   R.id.ClassRoom,R.id.Teacher, R.id.Weekday });
   listView.setAdapter(simpleAdapter);
   }
   });
                    }
                  
                  if(week=="3"){
                      listView=(ListView) findViewById(R.id.listView3);
   listView.post(new Runnable() {
   @Override
   public void run() {
   SimpleAdapter simpleAdapter = new SimpleAdapter(ClassSheet2.this, list,
   R.layout.csoutput,new String[] { "Jieci", "CourseName","ClassRoom",
   "Teacher", "Weekday" }, new int[] { R.id.Jieci,R.id.CourseName, 
   R.id.ClassRoom,R.id.Teacher, R.id.Weekday});
   listView.setAdapter(simpleAdapter);
   }
   });
                    }
                  
                  if(week=="4"){
                      listView=(ListView) findViewById(R.id.listView4);
   listView.post(new Runnable() {
   @Override
   public void run() {
   SimpleAdapter simpleAdapter = new SimpleAdapter(ClassSheet2.this, list,
   R.layout.csoutput,new String[] { "Jieci", "CourseName","ClassRoom",
   "Teacher", "Weekday"}, new int[] { R.id.Jieci,R.id.CourseName, 
   R.id.ClassRoom,R.id.Teacher, R.id.Weekday});
   listView.setAdapter(simpleAdapter);
   }
   });
                    }
                  if(week=="5"){
                      listView=(ListView) findViewById(R.id.listView5);
   listView.post(new Runnable() {
   @Override
   public void run() {
   SimpleAdapter simpleAdapter = new SimpleAdapter(ClassSheet2.this, list,
   R.layout.csoutput,new String[] { "Jieci", "CourseName","ClassRoom",
   "Teacher", "Weekday"}, new int[] { R.id.Jieci,R.id.CourseName, 
   R.id.ClassRoom,R.id.Teacher, R.id.Weekday});
   listView.setAdapter(simpleAdapter);
   }
   });
                    }
                  if(week=="6"){
                      listView=(ListView) findViewById(R.id.listView6);
   listView.post(new Runnable() {
   @Override
   public void run() {
   SimpleAdapter simpleAdapter = new SimpleAdapter(ClassSheet2.this, list,
   R.layout.csoutput,new String[] { "Jieci", "CourseName","ClassRoom",
   "Teacher", "Weekday"}, new int[] { R.id.Jieci,R.id.CourseName, 
   R.id.ClassRoom,R.id.Teacher, R.id.Weekday});
   listView.setAdapter(simpleAdapter);
   }
   });
                    }                 
                  if(week=="7"){
                      listView=(ListView) findViewById(R.id.listView7);
   listView.post(new Runnable() {
   @Override
   public void run() {
   SimpleAdapter simpleAdapter = new SimpleAdapter(ClassSheet2.this, list,
   R.layout.csoutput,new String[] { "Jieci", "CourseName","ClassRoom",
   "Teacher", "Weekday" }, new int[] { R.id.Jieci,R.id.CourseName, 
   R.id.ClassRoom,R.id.Teacher, R.id.Weekday });
   listView.setAdapter(simpleAdapter);
   }
   });
                    }
                  
                  }
             else  
              {  
                  result = "无此班级.";   
             }   
          }   
          catch (Exception e)   
          {   
             result = "调用WebService错误.";  
             e.printStackTrace();
          }         
          return null;   
      }   
  
  }   
    
    
    }
这是Activity C，没什么特殊处理呀。

Answer 5

你有重写对BACK键的处理么 
第一次点BACK，从C到B毫无疑问，第二次点BACK，实际上不期望返回上一个acitvity C （从C BACK回来的），而是系统任务栈里的上一个 A。

Answer 6

那意思就是说，要重写对back键的处理吗？

Answer 7

正常情况下是不用的 
误跳到C 如果不是你重写了BACK，那么就是对任务栈干扰操作

Answer 8

你是不是Actiivity C放到了堆栈最顶端？